#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/rope>

#define ff(i,a,b) for(int (i) = (a); (i) <= (b); ++(i))
#define fb(i,a,b) for(int (i) = (a); (i) >= (b); --(i))
#define mod 998244353
#define xx first
#define yy second
#define all(a) (a).begin(), (a).end()
#define pb push_back
#define ll long long
#define pii pair<int,int>
#define maxn 500005




using namespace std;
using namespace __gnu_pbds;

typedef tree<int, null_type, less<int>,rb_tree_tag, tree_order_statistics_node_update> ordered_set;/// find_by_order(x)(x+1th) , order_of_key() (strictly less)
mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());


int n,k;
int niz[maxn];

bool check(int x){
    int pref = 0;
    for(int l=0; l<=n; l++){
        if(l != 0){
            int staripref = pref;
            pref |= niz[l];
            if(pref == staripref)continue;
        }
        int ks = pref;
        int r = n;
        bool ima = 0;
        for(;r>=l+1; r--){
            ks |= niz[r];
            if( (ks - x) == (ks^x)){
                ima = 1;
                break;
            }
        }
        if(!ima)continue;
        ks = 0;
        int pomk = k;
        pomk--;
        for(int i=l+1; i<=r-1; i++){
            ks |= niz[i];
            if( (ks - x) == (ks^x)){
                pomk--;
                if(pomk == 0)return 1;
                ks = 0;
            }
        }
    }
    return 0;
}


int main()
{

    ios_base::sync_with_stdio(false); cin.tie(0);
    cin >> n >> k;
    ff(i,1,n)cin >> niz[i];
    if(k == 1){
        int sta = 0;
        ff(i,1,n)sta |= niz[i];
        cout << sta << endl;
        return 0;
    }
    int pref = 0;
    fb(i,29,0){
        bool sta = check(pref | (1<<i));
        if(sta)pref |= (1<<i);
    }
    cout << pref << endl;
    return 0;
}